/Engine/Source/Runtime/GeometryFramework/Public/Components/BaseDynamicMeshComponent.h
Secondary Render Buffers support. This requires implementation in subclasses. It allows a subset of the mesh triangles to be moved to a separate set of render buffers, which can then have a separate material (eg to highlight faces), or be shown/hidden independently. Set an active secondary render material.
virtual void SetSecondaryRenderMaterial ( [UMaterialInterface](API\Runtime\Engine\Materials\UMaterialInterface) * Material )